Cryogenic plants such as those found in natural gas processing and air separation are characterized by the use of a cold box. A cold box is an insulated enclosure which encompasses sets of process equipment such as heat exchangers, columns and phase separators. Such sets of process equipment may form the whole or part of a given process.
Chemical separation and liquefaction processes which occur at sub-ambient temperature are characterized by the need to mitigate ambient heat ingress. In addition, such processes are also characterized by the need to minimize lost work both in form of heat and mass transfer irreversibility. As a consequence, sub-ambient heat and mass transfer operations are often characterized by large distillation columns and by high area density heat exchange equipment. Given the size of the process equipment, the mitigation of heat ingress into this equipment is essential in order to minimize the need for additional refrigeration and associated power consumption.
The fabrication and shipment of process equipment packaged in a cold box may be constrained by numerous factors. In most instances, issues associated with transportation limit cold box specifications in terms of weight, length and cross section area and associated dimensions. The maximization of production capacity from a given cold box size/cross section would be very desirable.